Diborane reacts with ammonia under different conditions to give a variety of products. Which one among the following is not formed in these reactions?

The reagent used for converting acetylene to oxalic acid is

Two rain drops reach the earth with different terminal velocities having ratio $9:4$. Then the ratio of their volumes is

Steam at $100^{\circ} C$ is passed into $1 \ kg$ of water contained in a calorimeter of water equivalent $0.2 \ kg$ at $9^{\circ} C$ until the temperature of the calorimeter and water in it increases to $90^{\circ} C$. The mass of steam condensed in $kg$ is nearly (specific heat of water $= 1 \ cal/g^{\circ} C$,latent heat of vaporisation $= 540 \ cal/g$)

Identify from the following,a plant tissue in which lignin does not occur in the cell walls?

If $\frac{1 - \cos x}{\cos x(1 + \cos x)} = \frac{\sin \alpha}{\cos x} - \frac{2}{1 + \cos x}$,then $\alpha = $